Synergistic Catalysis at the Ni3Te2–Ni3C Heterointerface: Accelerating Water Dissociation for Efficient and Robust Hydrogen Evolution in Alkaline Water and Seawater

Abstract The alkaline hydrogen evolution reaction (HER) is kinetically limited by sluggish interfacial water dissociation and the subsequent hydrogen intermediate conversion, making the cooperative regulation of consecutive HER elementary steps crucial for achieving efficient electrocatalysis. However, most reported HER heterostructures primarily rely on global electronic structure modulation, while function-oriented interfacial regulation of distinct reaction steps remains insufficiently explored. Herein, a Ni3Te2–Ni3C heterostructure electrode was in situ fabricated on nickel foam via a one-step electrodeposition strategy and systematically evaluated for HER in both alkaline freshwater and alkaline seawater. Mechanistic investigations indicate that Ni3C promotes interfacial water activation and dissociation, whereas the Ni3Te2–Ni3C heterointerface further optimizes the kinetics of hydrogen intermediate conversion, thereby enabling the cooperative regulation of consecutive HER elementary steps. In situ Raman spectroscopy, together with density functional theory (DFT) calculations, provides supportive evidence for the facilitated water dissociation and optimized hydrogen intermediate conversion at the heterointerface. Benefiting from such functional complementarity, the optimized Ni3Te2–Ni3C/NF electrode requires overpotentials of only 26 and 32 mV to achieve 10 mA cm–2 in 1 M KOH and alkaline seawater, respectively, while maintaining good stability under the investigated operating conditions. This work establishes a structure–interface–activity relationship and provides a reaction pathway-oriented design principle for developing efficient alkaline HER electrocatalysts.